Narrow molecular weight margins for the thermogelling property of polyester–polyether block copolymers in aqueous solutions

Abstract

ABSTRACTPolyester–polyether block copolymers with thermogelling properties have been widely used in pharmaceutical and biomedical applications for their biocompatibility and degradation to nontoxic components. The biodegradable polymers, such as poly(lactide‐co‐glycolide) and poly(lactide‐co‐caprolactone) (PLCL), have been used as the polyester block. The most commonly used polyether has been poly(ethylene glycol) (PEG). The thermogelling polymers dissolve in cold water, but become a semisolid gel at higher temperatures, for example, body temperature. This thermogelling property, however, occurs only within very narrow molecular weight ranges of the polyester at given polyether blocks. Only a few hundred Dalton differences in the polyester block can turn a thermogelling polymer into a water‐insoluble polymer. This study describes the hydrophilic and hydrophobic block sizes for endowing the thermogelling property and a simple, water‐free, synthesis of new thermogelling PLCL–PEG–PLCL triblock polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48673.